This invention relates to mineral cutting apparatus, and in particular to a mounting member and a pick box for a cutter pick, for road planing apparatus or of mining or tunnelling machines.
Both road planing apparatus and a continuous mining machine comprise, respectively, a self-propelled wheeled or tracked chassis carrying a power driven drum. To the periphery of the drum is welded an array of pick boxes, each to receive a replaceable pick, usually having a tungsten carbide tip, possibly with a replaceable sleeve between the pick and the box.
Frequently, through poor practice, a lost or worn pick is not noticed or is ignore, resulting in wear and/or damage to the box. The worn box must be removed and a replacement box welded in place. Furthermore, the replaceable component(s), whether in the form of a pick or a sleeve, is replaceably secured by a compromise between a system that prevents inadvertent loss at unacceptable levels, yet one that permits on-site removal and replacement without too much difficulty.
A basic object of the invention is the provision of improved mineral cutting apparatus etc.
According to a first aspect of the present invention, there is provided a mounting member for a pick, for a mineral cutting apparatus, the member having:
(i) an enlarged head incorporating an annular seating shoulder;
(ii) a circular section pin extending integrally from the head and adapted to be received in a circular section socket of a pick box and to be retained therein;
(iii) a circumferential groove intermediate the ends of the pin to receive a fluid sealing member,
(iv) a first portion of the pin beyond the circumferential groove, remote from the head, being of such diameter that, in use, it is a slide fit within a pick box socket, and
(v) a second portion of the pin, between the groove and the head being of such diameter that, in use, it is an interference fit within a pick box socket.
In one embodiment, the enlarged head of the mounting member may be provided with an aperture appropriate to receive a shank of a mineral cutter pick, which shank aperture, for an asymmetrical mounting member is not coaxial with the longitudinal axis of the mounting member pin, but for a symmetrical mounting member ie a sleeve, is coaxial with the longitudinal axis of the mounting member pin.
In a second embodiment a block provided with a pick shank aperture may be welded to the enlarged head of the mounting member, preferably at a non-orthogonal angle (eg 20-25xc2x0, preferably 24.5xc2x0) to the longitudinal axis of the mounting member, so that if a pick is lost or damaged, resulting in damage to the enlarged head, the entire mounting member need not necessarily be scrapped, as there is the possibility of burning off the damaged portion and welding on a replacement portion, with attendant cost savings.
With an asymmetrical mounting member this is also provided with a location means to determine the orientation of the mounting member with respect to the pick box on which it is to be mounted. The locating means may take the form of a pin and hole arrangement. Thus, in detail a blind hole parallel to, but offset from, the longitudinal axis, may be drilled into the base of the pick to be engaged by an orientation pin of the pick box on which the mounting member is to be fitted.
Of whatever form, the mounting member or block is also preferably provided with an abutment surface extending orthogonally, or generally so, with respect to the longitudinal axis of the mounting member pin, whereby after the slide-fit, first portion of the mounting member pin has been fitted into the receiving aperture the interference fit, second portion may be forced in by hammering on the abutment surface.
Preferably, the seating shoulder extends radially. Preferably, the fluid sealing member is a resilient xe2x80x9cOxe2x80x9d-ring located in the circumferential groove engageable, in use, with a portion of the internal periphery of the pick box socket.
With an asymmetrical mounting member, its aperture to receive a pick shank is preferably so located that the end of the shank is accessible, so that a worn or damaged pick may be hammered out of its aperture.
According to a second aspect of the invention, there is provided a pick box adapted to be welded to the external periphery of a drum for a mineral cutting apparatus comprising:
(i) a blind circular socket adapted, in use, to receive and to retain as an interference fit a circular section pin of a replaceable mounting member, and
(ii) a bore communicating between the external periphery of the box and a portion of the socket.
whereby fluid such as grease or oil, introduced under pressure via the bore, serves to displace the pin from its aperture, when changing of a worn or damaged replaceable member is required.
At the external periphery of the box, the bore may be tapped to a receive a screw-in plug, which is removeable so that a connector fitting from a source of pressurised oil or grease, may be screwed in. Preferably however, a grease nipple is screwed into the tapped bore, eg by providing the grease nipple with a threaded spigot. Preferably, the box is provided with a recess in which the nipple can be accommodated so that it does not stand proud and hence is not prone to damage. The portion of the socket in communication with the bore, is preferably the bottom of the socket.
As the drum of a road planing machine for instance is conventionally provided with a spiral vane to assist in conveying spoil eg to a pick-up conveyor which may be located centrally of the machine, whereby vanes to opposite sides of the conveyor may be oppositely handed, preferably two selectable location means eg holes, are provided, with the appropriate location means selected for the handing of the vane. In detail, two spaced blind holes may be drilled into the base of the blind socket with a selected hole receiving one end of an orientation pin eg a roll pin.
According to a third aspect there is provided, in combination, a mounting member in accordance with the first aspect, mounted on a pick box in accordance with the second aspect.
Thus, the mounting member in accordance with the first aspect, pick box in accordance with the second, and combination in accordance with the third, provide the advantages that the mounting member may be hammered home into the pick box with the interference fit ensuring that the element cannot inadvertently be pulled from its box and lost eg when the direction of rotation of the drum is reversed, while the provision of an hydrauiic means of release and displacement ensures that, despite a tight interference fit, easy removal is ensured eg by applying a grease gun to the nipple.